Field of the Invention
The present invention relates to an electric stapler in which a level difference produced between a guide plate that feeds sheets of paper from a paper processing equipment provided in an image forming apparatus such as a copying machine or a printer to a stapler main body and a table provided on the stapler main body is eliminated.
Related Art
A stapler, equipped in a paper processing equipment provided in an image forming apparatus such as a copying machine or a printer, bounds a plurality of sheets as one set. A stapling action is carried out in such a manner that the sheets fed from the copying machine side are put on a guide plate, then the sheets are fed to a table provided to the stapler, and then the staple is driven into the sheets on the table. In order to align edges of the sheets, a receiving plane to which the edge of the sheets hits must be formed on the guide plate. Also, in order to feed the sheets to the table, a top end of the guide plate must be set at least on the table. However, if the guide plate is set directly on the table, the stapling action cannot be carried out owing to a hindrance of the guide plate. For this reason, an opening portion is formed in the guide plate by notching a portion corresponding to the table of the stapler, and the sheets are fed onto the table of the stapler in a state that the sheets on the guide plate are exposed from the opening portion. Also, there are a two-location binding and a corner binding as the stapler function. In order to respond to these modes, the opening portion is formed in the positions corresponding to the stapling locations respectively, then the guide plate is provided at a height that is contained in a space between the driver and the clincher of the stapler, then the stapler is moved up to the position of the opening portions in the guide plate along the side surface of the guide plate, and then the stapling action is performed.
Here, the table acts as a platform that is fixed on the stapler main body to staple the sheets. For example, in an apparatus in which the driver is driven to come close to the clincher fixed to the stapler main body, to perform the stapling action, the table is provided on a side of the clincher. When the driver comes close to the clincher, the sheets are pushed against a top surface of the table by the driver, and then the staple is driven toward clincher.
Meanwhile, when respective heights of a loading surface of the guide plate and the table of the stapler are different, the sheets on the guide plate are brought into a floating state over the table of the stapler. Therefore, when particularly a bundle of the sheets is thick, the bundle itself has rigidity and thus a bottom of the sheets cannot be firmly pushed against the table of the stapler in the stapling action. As a result, it is possible that the stapling failures are caused, e.g., a crown portion of the staple is lifted up from a surface of the sheets, a clinching of legs of the staple becomes insufficient, and the like.
As the measure taken against these failures, such an approach may be considered that the guide plate with small rigidity is arranged such that the guide plate is bent in the stapling action to bring the sheets into contact with the table of the stapler. However, when the guide plate with small rigidity is arranged, the guide plate itself is bent by a weight of the sheets if the number of sheets is large, so that a risk of a collision of the stapler main body with the guide plate is increased when the stapler is moved. Also, when the guide plate is set in a higher position than the table of the stapler to avoid such collision, such a problem arises that a space through which the sheets are inserted in the stapling action is decreased and thus a transfer of the sheets is disturbed.
As another measure, a technology to construct the stapler movably in a vertical direction and perform the stapling action after the table and the loading surface of the guide plate are set to constitute a substantially coplanar plane is known (see JP-A-07-215565).
However, according to the above technology, the stapler must be moved in not only a lateral direction but also the vertical direction. Therefore, a moving mechanism for moving the stapler is required on an outside of the stapler, so that such a situation cannot be avoided that an overall apparatus is made complicated and is increased in size.